Process for making calcium chlorides

Abstract

A new process for producing calcium chloride and other metal halides from the carbonates, bicarbonates, oxides of these metals. The process utilizes the discovery that hydrogen halides, when used in a true or conventional fluidizing medium in shallow beds of the aforementioned solids at moderately elevated temperatures in a continuous counter current process results in the conversion of the metal carbonates, bicarbonates, and oxides, into metal halides and carbon dioxide gas and/or water vapor. The process is carried out in a series of true or conventional fluidized beds preferable but not necessarily arranged in a vertical configuration so that the solids flow downward due to the fluidized process and the hydrogen halides flow counter currently in an upward direction producing metal halides at the bottom and pure carbon dioxide gas and/or water vapor at the top.

We claim:  
     
       1. A process for converting particulates of at least one selected from the group consisting of carbonates, bicarbonates, and oxides of a metal to corresponding halides, which is effective in the presence of air, comprising contacting the particulates with a fluidizing hydrogen halide gas at a velocity sufficient to form a true fluidized bed of the particulates, maintaining the true fluidized bed at a temperature in the range of from about 250° F. to about 800° F. for a time sufficient to permit the particulates to be converted to the corresponding halides while producing an effluent gas. 
     
     
       2. The process of  claim 1 , wherein the fluidizing hydrogen halide gas is selected from the group consisting of hydrogen chloride, hydrogen fluoride, hydrogen bromide and mixtures thereof. 
     
     
       3. The process of  claim 1 , wherein the metal is selected from the group consisting of sodium, calcium, magnesium, zinc, iron, and mixtures thereof. 
     
     
       4. The process of  claim 1 , wherein the particulates are selected from the group consisting of magnesite, dolomite, naturally occurring compounds of calcium, magnesium, zinc and iron, and mixtures thereof. 
     
     
       5. The process of  claim 1 , where a percentage of the effluent gas includes carbon dioxide and is recycled to sustain fluidization. 
     
     
       6. The process of  claim 5 , where the effluent gas contains carbon dioxide gas and is recovered. 
     
     
       7. The process of  claim 1 , where air is added to the fluidizing hydrogen halide gas or added separately to sustain fluidization. 
     
     
       8. The process of  claim 1 , wherein the true fluidized bed has a depth in a range of from about 12 inches to about four feet. 
     
     
       9. The process of  claim 1 , wherein the fluidizing hydrogen halide gas is maintained in contact with the particulates for a time sufficient to remove substantially all hydrogen halide from the effluent gas. 
     
     
       10. A process for converting particulates of at least one selected from the group consisting of carbonates, bicarbonates, oxides and hydroxides of a metal selected from the group consisting of alkali metals, alkaline metal earths, transition metals and mixtures thereof to corresponding halides, comprising establishing a series of fluidized beds of the particulates by passing a fluidizing gas containing hydrogen halide and air or recycled carbon dioxide through the particulates at a velocity sufficient to establish and maintain the particulates in a fluidized bed, the fluidizing gas leaving one fluidized bed and flowing through another fluidized bed in the series of fluidized beds until the fluidizing gas leaving the last fluidized bed in the series of fluidized beds is substantially free of hydrogen halide and the particulates leaving the first fluidized bed in the series of fluidized beds being substantially free of carbonates, bicarbonates, oxides or hydroxides. 
     
     
       11. The process of  claim 10 , wherein the fluidizing gas moves countercurrent to the direction of the particulates. 
     
     
       12. The process of  claim 10 , wherein the metal is selected from the group consisting of calcium, sodium, magnesium, zinc, iron, and mixtures thereof and the hydrogen halide is selected from the group consisting of hydrogen chloride, hydrogen fluoride, hydrogen bromide and mixtures thereof. 
     
     
       13. The process of  claim 10 , wherein the particulates are selected from the group consisting of limestone, magnesite, dolomite, naturally occurring compounds of calcium, magnesium, zinc and iron, and mixtures thereof. 
     
     
       14. The process of  claim 10 , where a percentage of the fluidizing gas leaving the last bed is carbon dioxide gas and is recycled to sustain fluidization. 
     
     
       15. The process of  claim 14 , where the carbon dioxide gas is recovered. 
     
     
       16. The process of  claim 10 , where air is added to the fluidized gas to sustain fluidization. 
     
     
       17. The process of  claim 10 , wherein each fluidized bed of the series of fluidized beds has a depth in a range of from about 12 inches to about four feet. 
     
     
       18. The process of  claim 10 , wherein the series of fluidized beds are in a single vessel vertically arranged such that particulates from one fluidized bed falls into a lower fluidized bed and gas exiting from a lower fluidized bed flows through a higher fluidized bed. 
     
     
       19. The process of  claim 10 , wherein the series of fluidized beds are vertically arranged such that particulates flow downwardly counter currently to the fluidizing gas flowing upwardly and particulates with a highest content of carbonates, bicarbonates, oxides or hydroxides are contacted with fluidizing gas having a lowest hydrogen halides content. 
     
     
       20. The process of  claim 10 , wherein the halide of the hydrogen halide is chloride and the metal is calcium.